Process for manufacturing ring-shaped member

ABSTRACT

A method of producing a ring-shaped member is provided in which a material loss is eliminated, the process cost can be reduced, and a ring-shaped member can be easily obtained from a pipe member by a small number of steps. The method includes steps of: inwardly projectingly shaping a flange portion  1   c  on an end portion of a metal-made pipe member  1 ; and cutting off the flange portion  1   c  from the pipe member  1 , thereby obtaining a ring-shaped member  10.

TECHNICAL FIELD

The present invention relates to a method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member.

BACKGROUND ART

Conventionally, for example, a ring-shaped member 10 such as shown in FIG. 2 is produced by a method in which, from a stock material 20 shown in FIGS. 3( a), (b) and having a predetermined thickness, a plurality of ring-shaped members 10 are punched out in a single or plural rows by a pressing apparatus.

In the conventional production method, however, the yield which is a ratio of the weight of the ring-shaped members 10 to that of the stock material 20 is poor, and hence the cost of the ring-shaped member 10 is increased. The reason is that the ratio of a skeleton S1 and a slug S2 to the ring-shaped member 10 is high in the material utilization. The term “skeleton” means a frame-like scrap which remains as a result of punching of the plurality of ring-shaped members 10. The term “slug” means a plurality of scraps which are removed by a punch in the process of punching out the plurality of ring-shaped members 10.

Therefore, a method of producing a ring-shaped member shown in FIG. 4 has been proposed (for example, see Patent Literature 1). The method of shaping a ring-shaped member is configured by steps of: longitudinally forming a slit 22 in the middle of a rectangular steel plate 21; pressingly expanding the slit 22 to obtain a polygonal member 23; and shaping angled portions 23 a and side portions 23 b of the polygonal member 23 into an arcuate shape which is circumferentially smooth, to obtain a ring-shaped member 10.

According to the method of producing a ring-shaped member, the shaping is performed by pressingly expanding the slit 22 of the rectangular steel plate 21. Therefore, the skeleton S1 and the slug S2 such as shown in FIG. 3 are not produced, a material loss can be reduced, and the process cost of the ring-shaped member 10 can be lowered.

Patent Literature 1: Japanese Patent Application Laying-Open No. 2004-188548 DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

In the method of producing a ring-shaped member disclosed in Patent Literature 1, in order to obtain a ring-shaped member from a steel plate member serving as a stock material, however, a step of cutting the steel plate member into a rectangular shape to obtain the rectangular steel plate 21 is necessary, and then many further steps such as steps of: forming the slit 22 in the middle of the rectangular steel plate 21 by gas, plasma, or laser; pressingly expanding the slit 22 by an apparatus consisting of male and female dies and a shaping die to obtain the polygonal member 23; and, by the shaping die, shaping the angled portions 23 a and side portions 23 b of the polygonal member 23 into an arcuate shape which is circumferentially smooth are required. The steps are complicated.

The invention has been conducted in order to solve the problems. It is an object of the invention to provide a method of producing a ring-shaped member in which a material loss is eliminated, the process cost can be reduced, and ring-shaped members can be easily continuously obtained from a pipe member by a small number of steps.

Means for Solving the Problems

The invention according to claim 1 provides a method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member, wherein the method includes steps of: inwardly projectingly shaping a flange portion on an end portion of the pipe member; and cutting off the flange portion from the pipe member, thereby obtaining a ring-shaped member.

According to the configuration, the flange portion is inwardly projectingly shaped on an end portion of the pipe member, and the flange portion is cut off from the pipe member to obtain the ring-shaped member. Therefore, the skeleton S1 and the slug S2 such as shown in FIG. 3 are not produced, a material loss can be eliminated, and the process cost of the ring-shaped member can be lowered.

Furthermore, ring-shaped members can be easily continuously obtained from the pipe member by the small number of steps, or namely, the step of inwardly projectingly shaping a flange portion on an end portion of the pipe member, and that of cutting off the flange portion from the pipe member.

The invention according to claim 2 provides a method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member, wherein the method includes steps of: inwardly bending a whole circumference of an end portion of the pipe member to shape a tapered truncated conical tubular portion; further inwardly bending the truncated conical tubular portion to shape a flange portion which is inwardly projected; and cutting off the flange portion from the pipe member, thereby obtaining a ring-shaped member.

According to the configuration, in a similar manner as the invention set forth in claim 1, the skeleton S1 and the slug S2 such as shown in FIG. 3 are not produced, a material loss can be reduced, the process cost of the ring-shaped member can be lowered, and ring-shaped members can be easily continuously obtained from the pipe member. Moreover, the truncated conical tubular portion is shaped before the shaping of the inward flange portion on an end portion of the pipe member. Even when the pipe member is thick, therefore, the flange portion can be shaped in a thickness which is uniform as far as possible, while avoiding local thinning, as compared with the case where a perpendicular flange is directly shaped on an end portion of a pipe member.

EFFECTS OF THE INVENTION

The invention has advantages that ring-shaped members can be easily continuously obtained from a pipe member while eliminating a material loss, and by the small number of steps, and that the process cost of a ring-shaped member can be lowered.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a step section view of a method of producing a ring-shaped member showing an embodiment of the invention.

FIG. 2 is a plan view showing an example of a ring-shaped member.

FIG. 3 is a plan view showing a conventional step of punching out blanks from a stock material, (a) shows single-row punching, and (b) shows parallel punching.

FIG. 4 is a step diagram of a method of producing a ring-shaped member disclosed in Patent Literature 1.

DESCRIPTION OF REFERENCE NUMERALS

-   1 pipe member -   1 a end portion -   1 b truncated conical tubular portion -   1 c flange portion -   10 ring-shaped member

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the method of producing a ring-shaped member related to the invention will be described with reference to the drawings.

FIG. 1 is a step section view of a method of producing a ring-shaped member showing an embodiment of the invention.

As shown in FIG. 1( a), first, a pipe member 1 having a circular section made of a metal such as soft steel, copper, aluminum, iron, or stainless steel is set in a press processing apparatus 2. The press processing apparatus 2 includes: a punch 3 which is to be passed through the pipe member 1; a punch outer 4; a first die 5; and a first center pin 6. The first die 5 has a die hole 7 which is opposed to the tip end of the punch 3, and which has a dish-like section shape that is outward expanded. A tip end portion 6 a of the first center pin 6 having an outer diameter which is smaller than the inner diameter of the pipe member 1 is protruded into the die hole 7.

The pipe member 1 is set so that its end portion 1 a is protruded by a predetermined distance from a tip end portion of the punch 3.

As shown in (b) of the figure, next, the punch 3 and the first die 5 are relatively moved so as to approach each other, and the end portion 1 a of the pipe member 1 is caused to enter between the tapered inner circumference of the die hole 7 having a dish-like section shape, and the outer circumference of a protruded tip end portion 6 a of the center pin 6, whereby the whole circumference of the end portion 1 a of the pipe member 1 is inwardly bent to shape a tapered truncated conical tubular portion 1 b (namely, a truncated conical tubular portion shaping step).

As shown in (c) of the figure, then, at a processing position which includes: a second die 8; a first ejector 9 that is passed through a die hole 8 a of the die 8, and that has a substantially same diameter as the inner diameter (the outer diameter of the punch 3) of the pipe member 1; and a second center pin 11 that is passed through a center hole 9 a of the ejector 9, and that has a substantially same diameter as the inner diameter of a ring-shaped member 10 (see FIG. 2), and in which a tip end portion 11 a of the second center pin 11 is protruded from the tip end of the first ejector 9, the second die 8, the first ejector 9, and the second center pin 11 and the punch 3 are relatively moved so as to approach each other, and the tip end of the first ejector 9 is pressed against the truncated conical tubular portion 1 b, whereby the truncated conical tubular portion 1 b is bent until it is substantially perpendicular to the axis of the pipe member 1 to shape a flange portion is which is inwardly projected (namely, a flange portion shaping step).

As shown in (d) of the figure, finally, at a processing position which includes: a third die 12; and a second ejector 13 that is passed through a die hole 12 a of the die, and that has a substantially same diameter as the inner diameter (the outer diameter of the punch 3) of the pipe member 1, the third die 12, and the second ejector 13 and the punch 3 are relatively moved so as to approach each other, so that the flange portion 1 c is pressed against the tip end of the punch 3 by the second ejector 13. The third die 12 is relatively moved so as to further approach the punch 3, so that a shearing force acts between the die 12 and the punch 3, and the punch 3 and the edge of the die 12 bites in a base portion of the flange portion 1 c to shear it, whereby the flange portion is cut off from the pipe member 1, and the ring-shaped member 10 (see FIG. 2) can be obtained (namely, a flange portion cutting off step).

When the truncated conical tubular portion shaping step (FIG. 1( b)), the flange portion shaping step (FIG. 1( c)), and the flange portion cutting off step (FIG. 1( d)) are sequentially repeated, it is possible to continuously produce ring-shaped members 10.

According to the production method of the embodiment, without producing the skeleton S1 and the slug S2 such as shown in FIG. 3, and without forming a material loss, many ring-shaped members 10 can be continuously produced from one pipe member 1 by the pressing process. Furthermore, the ring-shaped member 10 can be easily obtained from the pipe member 1 by the small number of steps, or namely, the step of projectingly shaping the flange portion 1 c on the end portion of the pipe member 1, and that of cutting off the flange portion 1 c from the pipe member 1. Therefore, the process cost of the ring-shaped member 10 can be lowered.

In the embodiment, the truncated conical tubular portion shaping step (FIG. 1( b)) is performed to shape the truncated conical tubular portion 1 b, before the shaping of the flange portion 1 c on the end portion of the pipe member 1. However, the truncated conical tubular portion shaping step is not always necessary. Without performing the truncated conical tubular portion shaping step, the flange portion is may be inwardly projectingly shaped on the end portion of the pipe member 1.

In the process of inwardly projectingly shaping the flange portion is on the end portion of the pipe member 1, it is not restricted to employ the press processing apparatus 2 as in the embodiment. The flange portion 1 c may be shaped by another flange processing apparatus. 

1. A method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member, wherein said method includes steps of: inwardly projectingly shaping a flange portion on an end portion of said pipe member; and cutting off said flange portion from said pipe member, thereby obtaining a ring-shaped member.
 2. A method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member, wherein said method includes steps of: inwardly bending a whole circumference of an end portion of said pipe member to shape a tapered truncated conical tubular portion; further inwardly bending said truncated conical tubular portion to shape a flange portion which is inwardly projected; and cutting off said flange portion from said pipe member, thereby obtaining a ring-shaped member. 